1. Field of the Invention
The present invention pertains to an air and liquid separator particularly useful in an extraction type carpet cleaner.
2. Summary of the Prior Art
Carpet extractors generally spray or otherwise deposit, a cleaning liquid, such as water or a suitable cleaning solution, upon the carpet or other surface to be cleaned, followed by removal of the deposited liquid, along with dirt entrained in the liquid, by a suction nozzle. The soiled liquid and other debris is then separated from the working air and collected in a recovery tank.
Satisfactory separation of liquid and debris from the working air is difficult to obtain in upright style carpet extractors, such as the extractor diagrammatically illustrated in FIG. 1. Unlike canister type carpet extractors and wet/dry utility vacuum cleaners that have a relatively large recovery tank or canister portion, the space available in an upright carpet extractor for the separation and recovery of liquid entrained in the working air is relatively small. In the relatively large recovery tanks provided in canister style wet pickup suction cleaners, the liquid laden working air experiences a large degree of expansion and slowing upon entering the tank. This expansion and slowing of the working air is typically sufficient to adequately separate the liquid from the working air. In the relatively small spaced provided in the recovery tank of an upright carpet extractor, the liquid laden working air travels through the recovery tank much too fast with too little expansion for the liquid to adequately separate from the air, unless special structure is provided in the tank to cause the liquid to separate from the air. Tortuous air flow paths in the recovery tank or in an associated separator are typically used to enhance separation of the entrained liquid and dirt from the working air.
Commonly owned U.S. Pat. No. 5,500,977 and No. 5,779,744 both disclose a recovery tank on an upright carpet extractor. The lid on the recovery tank in each of these patens is hollow and defines an inlet chamber and an outlet chamber that communicate with the recovery tank. The inlet chamber in the lid, combined with the tank itself, forms a separator for separating liquid and other debris from the liquid laden air traveling through the lid and through the recovery tank and collecting the separated liquid and debris in the tank. The 5,500,977 patent teaches a relatively large circular discharge opening in a lower wall of the lid communicating the inlet chamber with the interior of the recovery tank. In the ""977 device, the liquid laden air performs a ninety degree turn upon entering the inlet chamber, a ninety degree turn traveling through the inlet chamber, and a ninety degree upon passing through the discharge opening and into the recovery tank. The ""744 patent discloses a plurality of relatively small discharge openings in the lower wall of the lid. The liquid laden air travels sequentially over the plurality of discharge openings, with a portion of the air passing through each opening into the recovery tank.
The separator/recovery tanks provided on prior upright carpet extractors perform adequately on the carpet extractors for which they were designed. However, it is desirable to increase the ability of the machine to extract soiled liquid from a carpet. The machines ability to extract liquid from a carpet is most readily increased by increasing the rate of airflow through the suction nozzle. Increasing the airflow through the nozzle increases the airflow through the separator/recovery tank. The result is an increase in the speed at which the liquid laden working air travels through the recovery tank lid and through the recovery tank itself. The prior art recovery tanks and lids are unable to adequately separate the liquid from the working air at the desired increased flow rates. When the flow rate through the nozzle and the separator was increased to the desired level using the existing separators, liquid passed through the recovery tank and entered the motor fan assembly, creating a potentially hazardous situation.
It is also desirable to provide a carpet extractor having a wider nozzle for cleaning a wider swath of carpet in a single pass. In order to maintain the ability of the machine to extract liquid from the carpet using a wider suction nozzle, the rate of airflow must be increased due to the increased size of the nozzle. As described above, the existing separators are unable to satisfactorily separate liquid and other debris from the working air when the rate of airflow through the separator is increased.
An object of the present invention is to provide an improved air and water separator for use with wet pickup floor care appliances. More particularly, it is an object of the present invention to provide a separator for an upright carpet extractor having enhanced air and water separation, in order to enable an increased rate of air flow through the separator compared to existing upright carpet extractors.
The foregoing and other objects of the present invention, that will be readily apparent from the following description and the attached drawings, are achieved in a preferred embodiment of the present invention by providing an air/liquid separator for use on a wet pickup suction cleaner and more specifically for use on an extractor having an upright configuration as illustrated in FIG. 1. In an upright extractor it is preferred that the recovery tank and air/liquid separator be combined into one removable assembly for ease of emptying the recovered cleaning solution. It is further desirable that the separator incorporate means whereby the operator may visually observe the flow of extracted liquid recovered by the extractor.
In one form or preferred embodiment of the present invention, the recovery tank is provided with a hollow, preferably transparent, removable lid having a wall therein dividing the lid into two separate chambers, an inlet/separating chamber and an exit chamber. Liquid and dirt laden working air preferably vertically enters an inlet opening to the inlet chamber, immediately negotiates a ninety degree turn to the horizontal, and flows horizontally across the inlet chamber over an elongate discharge opening in the lid bottom plate. The stream of dirty liquid and air is redirected downward through the discharge opening into the recovery tank. The incoming liquid and dirt entrained working air thus experiences a tortuous turn, and an expansion immediately upon entering the inlet chamber, followed by a second tortuous turn downward through the lid discharge openings. The liquid laden air undergoes further expansion and deceleration upon entering the recovery tank, where final separation of the liquid and entrained dirt from the working air occurs.
In a preferred embodiment of the present invention, a plurality of ribs are located in the inlet chamber in the lid progressively along the stream of liquid and air entering and flowing across the inlet chamber. First and second ribs extend down from the lid top plate into the inlet chamber. The first and second ribs extend approximately half the distance between the lid top plate and the lid bottom plate. The liquid laden air impinges on the first and second ribs and is at least partially redirected down into the recovery tank. The first and second ribs are also preferably inclined relative to stream of air in the inlet chamber, whereby the first and second ribs force the remaining air traveling through the inlet chamber through a twisting zig-zag pattern.
The exit chamber also fluidly communicates with the interior of the recovery tank through an exit opening passing through the lid bottom plate. A vacuum is preferably drawn upon the exit chamber by the extractor suction fan, thereby providing the required working air flow into and out of the combined air/liquid separator and recovery tank.